Un facteur commun est (x - 2).
(x - 2)(x + 3) + (x - 2)(3x - 2)
= (x - 2)[(x + 3) + (3x - 2)]
= (x - 2)(x + 3 + 3x - 2)
= (x - 2)(4x + 1) .

(3 - x)(x + 7) + (x + 7)(2 - x)
= (x + 7)[(3 - x) + (2 - x)]
= (x + 7)(3 - x + 2 - x)
= (x + 7)(5 - 2x) .

(x - 7)(x + 3) + (x - 2)(3x - 2)
= (x - 7)[(3x + 2) - (1 - 2x)]
= (x - 7)(3x + 2 - 1 + 2x)
= (x - 7)(5x + 1) .

(2x - 5)(5x - 3) - x(5x - 3)
= (5x - 3)(2x - 5 - x)
= (5x - 3)(x - 5) .

(2x + 1)² + (2x + 1)(x + 7)
(2x + 1)(2x + 1 + x + 7)
= (2x + 1)(3x + 8) .

(x + 3)(3x - 5) + (x + 3)*1
(x + 3)[(3x - 5) + 1]
= (x + 3)(3x - 4) .